refactor: update CHANGELOG.md

Author: rickstaa

CHANGELOG.md

@@ -13,6 +13,7 @@ Requires `libfranka` >= 0.8.0
   * `franka_gazebo`: `FrankaHWSim` only acts on joints belonging to a Franka robot. This allows to combine a Franka robot and others (like mobile platforms) in same URDF ([#313](https://github.com/frankaemika/franka_ros/issues/313))
   * `franka_description`: `<xacro:franka_robot/>` macro now supports to customize the `parent` frame and its `xyz` + `rpy` offset
   * `franka_hw`: Fix the bug where the previous controller is still running after switching the controller. ([#326](https://github.com/frankaemika/franka_ros/issues/326))
+  * `franka_gazebo`: fix `tau_ext` calculation bug
 
 ## 0.10.1 - 2022-09-15